WO2006004583A2

WO2006004583A2 - Process for producing synthetic liquid hydrocarbon fuels

Info

Publication number: WO2006004583A2
Application number: PCT/US2005/012612
Authority: WO
Inventors: Dennis R. Hardy; Timothy Coffey
Original assignee: US Department of Navy
Current assignee: US Department of Navy
Priority date: 2004-04-15
Filing date: 2005-04-14
Publication date: 2006-01-12
Anticipated expiration: 2006-10-15
Also published as: US7420004B2; WO2006004583A3; US20050232833A1

Abstract

Process and composition, in particular for controlling ticks on animals, characterized in that the composition includes, on the one hand, at least one compound of IGR (insect growth regulator) type, in doses and proportions which are parasiticidally effective on ticks, in a fluid vehicle which is acceptable for the animal and convenient for local application to the skin, preferably localized over a small surface area.

Description

PROCESS FOR PRODUCING SYNTHETIC LIQUID HYDROCARBON FUELS

BACKGROUND OF THE INVENTION

Field of the Invention: The present invention relates to hydrocarbon production and, more

specifically, to a process to make synthetic liquid hydrocarbons from carbon dioxide,

obtained from seawater or air, and hydrogen from water without the use of fossil fuels in any step of the process. Description of the Related Art

Description of Prior Art: The United States Navy uses over a billion gallons of liquid

hydrocarbon fuel each year. The fuel is procured from petroleum refineries and suppliers around the world and is transported to its final location of use. This can involve fuel

shipments over thousands of miles and many weeks of transport. Moreover, implementing

fuel cells on ships requires a hydrogen carrier such as liquid hydrocarbon fuels that are extremely low in sulfur content since this contaminant will poison the fuel cell fuel reformer.

Although the idea for developing synthetic liquid hydrocarbon fuels has been

discussed for at least the last 30 years, there has not been an apparent need to produce them

because of the availability, ease of processing, and high-energy conversion efficiency of fossil

fuels. However, the fossil fuel market is changing. One reason for this change is the ongoing

political instability in oil producing regions. Another reason is the increasing worldwide

energy demand.

There are several disadvantages to using fossil fuels. First, fossil fuels are a limited

resource that cannot be regenerated. Additionally, hydrocarbon fuels made from fossil fuels

may contain highly undesirable sulfur, nitrogen, and aromatic compounds. When these fuels are burned, sulfur, nitrogen, and particulates are released into the air, which leads to the

formation of acid rain and smog.

There are several well-established processes for direct hydrogenation of gases such as

CO or CO₂ to produce hydrocarbon fuels. One of the most successful was developed in

Germany in the 1920s by Franz Fischer and Hans Tropsch. hi 1938, early German plants

produced 591,000 metric tons per year, approximately 5 x 10⁶ barrels per year or

approximately 2 x 10⁸ gallons/year, of oil and gasoline using the Fischer-Tropsch process, which reacts carbon monoxide and hydrogen with a catalyst to produce liquid hydrocarbons

and water. The problem with these methods is that they use fossil fuels to produce the CO,

CO₂, and H₂ used.

Additionally, well-known methods have been developed to produce methanol from

carbon dioxide and hydrogen. One successful process is the Lurgi process. Methanol can also

be used as a feedstock to produce traditional automotive gasoline. The problem with these

methods is that the flash point of methanol is 11°C and the flash point of gasoline is well

below 0°C. Therefore, these methods cannot be used at sea, since the International Maritime

Organization and the U.S. Navy require a minimum 60°C flash point for all bulk flammable

liquids on ships.

SUMMARY

The aforementioned problems are overcome by the present invention wherein the

desired synthetic hydrocarbons are produced by reacting carbon dioxide, obtained from

seawater or air, and hydrogen from water with a catalyst in a chemical process such as reverse

water gas shift combined with Fischer Tropsch synthesis. The reverse water gas shift (CO₂ + H₂ → CO + H₂O) produces carbon monoxide, which is reacted with hydrogen in the Fischer

Tropsch synthesis to produce synthetic liquid hydrocarbons and water. Alternatively, a Lurgi

process can be used for intermediate method production, which can be used in the Fischer

Tropsch synthesis. The present invention can be either land based of sea based.

In a preferred embodiment, carbon dioxide is recovered by partial vacuum degassing during the pumping of seawater from any depth, extraction from seawater by any other

physical or chemical process, absorption from air by any known physical or chemical means, or any combination of the above methods.

Hydrogen is produced by standard electrolysis of water using electrodes, thermolysis

of water (for example using waste heat from nuclear reactors), thermochemical processes, and

any combination of the above methods. Energy for the hydrogen production can be provided by nuclear reactor electricity; nuclear reactor waste heat conversion; a thermochemical

process; ocean thermal energy conversion to electricity; any other source of fossil fuel free

electricity such as ocean waves, wind, tides or currents; or any combination of the above

methods.

The catalyst for the Fischer Tropsch reaction can be a metal such as iron, cobalt,

nickel, and combinations thereof; a metal oxide such as iron oxide, cobalt oxide, nickel oxide,

ruthenium oxide, and combinations thereof; support type material such as alumina or zeolites;

supported metals, mixed metals, metal oxides, mixed metal oxides; and any combination of

the above.

Unique benefits of liquid hydrocarbons produced according to this invention include:

they have no sulfur content, they have no nitrogen content, they have no aromatics content, they have high volumetric and gravimetric energy density, they have an excellent resistance to

thermal oxidation processes, they are fire safe (i.e., they are hard to ignite), they have good

low temperature properties, they can be reformed easily for production of hydrogen in fuel

cell applications, they are produced without using fossil fuels, the process is carbon neutral

when

combusted, the starting materials are cost free, and in situ production of stored energy

requires no large storage volumes or long distance transport for naval uses. Additionally, an equal volume of fresh water is produced as a useful byproduct.

DETAILED DESCRIPTION OF THE INVENTION

In a preferred embodiment of the present invention, carbon dioxide and hydrogen are

used to produce synthetic liquid hydrocarbons. Using the reverse water gas shift, carbon dioxide is reduced by hydrogen to carbon monoxide and water. See, for example, Cheryl K.

Rofer-DePoorter, "Untangling the Water Gas Shift from Fischer-Tropsch: A Gordian Knot?"

the Geochemistry Group, Los Alamos National Laboratory, P.O. Box 1663, MS D462, Los

Alamos, NM 87545 (1983) , the entire contents of which are incorporated herein by

reference. The water is recovered and the carbon monoxide is fed along with additional

hydrogen to a Fischer Tropsch based (catalyzed) reactor that produces equal volumes of fresh

water and liquid hydrocarbon as the final products of value. The resulting liquid hydrocarbons

of the desired molecular weight and shape are free of sulfur, nitrogen, and aromatics, so they

can be further processed to make a cyclic unsaturated material that could be supplied to all

current types of engines, such as compression ignition, internal combustion, and gas turbine

based engines. Alternatively, carbon dioxide and hydrogen may be catalyzed to form methanol and water. The materials are recovered and the methanol is immediately fed to a

Fischer Tropsch based reactor along with additional hydrogen to form the desired synthetic

liquid hydrocarbons.

The source of carbon is dissolved carbon dioxide in the ocean or the air. The recovery

of carbon dioxide from seawater may be by degassing of subsurface water or by some

other means of recovery from water such as membranes. There are many known procedures

for physically or chemically removing carbon dioxide from seawater or air that may be used, such as by extraction or absorption. See, for example, S. Locke Bogart, "White Paper on

Production of Liquid Hydrocarbons from High Temperature Fission Reactors for Department

of Defense and Commercial Applications," produced by EASI for General Atomics, January

31, 2004; and G. Gran, "Determination of the equivalence point in potentiometric titrations," , The Analyst, 22, 661-671, 1952, the entire contents of both are incorporated herein by

reference.

The degassing apparatus consists of any water pump fitted with a chamber for

collecting the gasses collected from seawater by partial vacuum. The carbon dioxide collected

in the chamber can be continually fed into the chemical reactors to just sustain the production

of the liquid hydrocarbon products at the desired rate.

The source of hydrogen can be from ocean thermal energy conversion (OTEC). OTEC

generates electricity, which can be used to electrolyze water to produce hydrogen. The use of

OTEC is restricted to the tropical oceans where there is a greater than 18 °C temperature

gradient between surface and subsurface waters. Alternatively, nuclear power plants can be

used as a source of electricity, nuclear reactor waste heat can be used to produce hydrogen, or thermochemical processes can also be used. OTEC, nuclear reactor electricity, nuclear waste heat conversion, and thermochemical processes can also be used to provide the energy required for degassing.

The electricity needed to produce the hydrogen comes from nuclear reactors, OTEC

generators, any other fossil fuel free source such as wind, wave, tidal or ocean current

sources, or any combination of the above sources. While fossil fuels maybe used as energy

sources for this process, their use will lower the net energy obtained from the production of

hydrocarbons by this invention. The standard water/steam generators from nuclear reactors are well known. The

low temperature generator cycles from OTEC are also well known. An added benefit of using

OTEC as part of the entire coupled process of producing liquid hydrocarbons is that pumping large volumes of water is integral to the process of generating electricity and the same pumped water can serve as the source of carbon dioxide.

Commercial electrolyzers are available to electrolyze water for the production of hydrogen needed as a reactant in the production of the hydrocarbons. Alternatively, known

methods such as thermolysis, i.e., heat assisted electrolysis, are available, if sufficient heat

from nuclear reactors is available. Finally, known thermochemical processes are also

available for hydrogen production using even less energy.

The chemical reactions are carried out using the gas phase reactants ,i-e-, carbon

dioxide and hydrogen, obtained from the air, water, or both, at rates necessary to sustain the

reactions and produce required amounts of liquid hydrocarbon product. A preferred

embodiment involves standard, well known fixed bed or slurry type flow reactor systems through catalyst beds at established temperatures, pressures, and flow rates. A preferred

embodiment for a shipboard application includes the joining of reactors for a catalytic

methanol production with immediate reaction of the methanol plus hydrogen to form liquid hydrocarbons for shipboard use.

The Fischer Tropsch synthesis reacts gaseous sources of carbon less oxidized than

CO₂ i.e., such as carbon monoxide or methanol, and hydrogen with a catalyst to obtain water

and liquid hydrocarbons, see, for example, A. Hoff, "CO Hydrogenation Over Cobalt

Fischer-Tropsch Catalysts," Norges Tekniske Hoegskole (1993); A. O. I. Rautavouma, "The

Hydrogenation of Carbon Monoxide on Cobalt Catalysts," Technische Hogeschool

Eindhoven

(1979); and Cheryl K. Rofer-DePoorter, "Untangling the Water Gas Shift from ^• Fischer-Tropsch: A Gordian Knot?" the Geochemistry Group, Los Alamos National

Laboratory, 1983; P.O. Box 1663, MS D462, Los Alamos, NM 87545 (1983); all of which are incorporated herein by reference in their entirety:

CO + H₂ - R-(CH₂)_nR + H₂ O or CH₃ OH + H₂ → R - (CH ₂) _n - R + H ₂0 where R is branched methylene or a terminal methyl group.

Typical conditions for this reaction on iron, cobalt, or mixed metal catalyst beds are as

follows: for example, for iron or cobalt the temperature range is 178°C to 320°C and the

pressure range is 1-10 MPa. The reaction is very exothermic and produces waste heat that can

be used to produce electricity with a theoretical maximum of about 10 kW/1000 gallons.

Two different reactions can be used to obtain the reactants for the Fischer Tropsch

reaction: the well known reverse water gas shift and the well-known Lurgi process, also known as the Carnol process. In the reverse water gas shift reaction, carbon dioxide is reacted

with hydrogen to produce carbon monoxide and water:

CO ₂ + H ₂ → CO + H ₂O

Typical conditions for reverse water gas shift reactions are temperatures between 200 and

400°C near atmospheric pressure in the presence of catalysts such as iron. See, for example,

Pradyot Patnaik, "Handbook of Inorganic Chemicals," published by McGraw-Hill, 2003, the

entire contents of which are incorporated herein by reference. The carbon monoxide produced

from this reaction is then used in the Fischer Tropsch synthesis to obtain liquid hydrocarbons.

The Carnol or Lurgi process uses the same reactants as the reverse water gas shift

reaction with different catalysts and reaction conditions to produce methanol, see, for example, Y. Miyamoto et al., "Methanol Synthesis from Recycled Carbon Dioxide and

Hydrogen from High Temperature Steam Electrolysis with the Nuclear Heat of an HTGR,"

IAEA-TECHDOC - 761, PP 79-85; Jamil Toyir et al., "Methanol Synthesis from CO2 and H2 over Gallium Promoted Copper-based Supported Catalysts. Effect of Hydrocarbon Impurities

in the CO2/H2 Source," Phys. Chem. Chem. Phys., 3, 4837-4842 (2001); M. Lachowska and

J. Skrezypek, "Hydrogenation of carbon dioxide to methanol over Mn promoted

copper/zinc/zirconia - catalysts," Proceedings of the 30th International Conference of the

SSCHE, May 26-30, 2003; and Hermann Goehna and Peter Koenig, "Producing Methanol

from CO2," CHEMTECH, June 1994):

CO ₂ + 3 H ₂ → CH ₃OH + H ₂O

An example of reactor conditions is as follows: Cu/CuO or Cu/ZnO as the catalyst, a

temperature of between 200 and 300°C, a pressure in the range of 40-100 bar, and a flow of 8120 L/hr. The methanol produced from this reaction is then used in the Fischer Tropsch

synthesis to obtain liquid hydrocarbons.

The reverse water gas reaction may be accomplished with or without the use of catalysts. The Fischer Tropsch synthesis is accomplished using a catalyst, as is the Carnol or

Lurgi process. Catalysts that may be used for Fischer Tropsch synthesis and the reverse water

gas reaction, if desired, include metals such as iron, cobalt, nickel; a combination of metals; metal oxides such as iron oxide, cobalt oxide, nickel oxide, and ruthenium oxide; a

combination of metal oxides; support type materials such as alumina and zeolites; supported

metals, mixed metals, metal oxides, or mixed metal oxides; and any combination of the

above. See, for

example, A. Hoff, "CO Hydrogenation Over Cobalt FiscberrTropsch Catalysts," TMorges _:. .. Tekniske Hoegskole (1993); and Cheryl K. Rofer-DePoorter, "Untangling the Water Gas

Shift from Fischer-Tropsch: A Gordian Knot?" the Geochemistry Group, Los Alamos National Laboratory, P.O. Box 1663, MS D462, Los Alamos, NM 87545 (1983), both of

which are incorporated herein by reference in their entirety. Examples of typical catalysts for

the Carnol or Lurgi process included supported Cu-Mn oxide and supported Cu-Zn oxide.

See, for example, M. Specht, A. Bandi, M. Elser, and F. Staiss, "Comparison of CO2 sources

for the synthesis of renewable methanol," Advances in Chemical Conversion for Mitigating

Carbon Dioxide Studies in Surface Science and Catalysis, Vol. 114, T. Inui, M. Anpo, K.

Izui, S. Yanagida, T. Yamaguchi (Eds.) 363-367 (1998), the entire contents of which is

incorporated herein by reference.

The present invention can be either land based or ship based. For a land-based process using OTEC, an island near the equator (for example the Cayman Islands, the Philippines, or

Guam) can be used to extend a pipe down into the water. For a ship-based process, energy can be obtained by OTEC or from the ship's nuclear reactor.

In a preferred embodiment, the limiting reagent or factor typically will be electricity

produced from fossil fuel free sources. In a land-based embodiment, this electricity will only

be limited by the size of the land based power availability; the size of the land based OTEC

plant; or the size of the wind, wave, tidal or ocean current facility. In an ocean based embodiment, the

electricity available will be limited to a fraction of the largest nuclear power plants installed

on naval ships or to a maximum of about 200 megawatts from an OTEC ship. , . ^■■ . ,•.

This limiting factor, i.e.* electricity,, will determine the maximum amount of hydrogen that can be generated and the maximum rate at which hydrogen can be generated, after other

electrical operating needs have been met. The hydrogen generation rate and daily production

will in turn define the required daily production and rate of carbon dioxide recovery from

ocean water, air, or both.

The maximum carbon dioxide recovery from water would be about 0.1 grams per

liter, and the maximum recovery from air would be about 0.00047 grams per liter. The actual

recovery rate and daily recovery will depend greatly on which of the many chemical, physical

or combined type processes is selected for recovery, as they vary greatly in their recovery

efficiencies. The most limited case for carbon dioxide recovery would be an ocean based

embodiment.

Given the potential limiting factors for the most limiting case of embodiments available, both reactant generation rates must be adjusted so that they are consumed as they

are produced during the final step of synthetic liquid hydrocarbon production in typical well

known catalytic processes based on the Fischer Tropsch synthetic process.

The preferred embodiment will produce synthetic liquid hydrocarbons at a rate and

daily production that is dependent upon the limitations described above. A typical production

of about 100,000 gallons per day (about 4,000 gallons per hour) of approximately an average molecular weight of 150 daltons is possible for ocean-based embodiments with fossil fuel

free electricity of about 100 mega watts. A land-based embodiment would typically be a

multiple of this.

The above description is that of a.preferred embodiment of the invention. Various_f

modifications and variations are possible in light of the above teachings. It is therefore to be . understood that, within the scope of the appended claims, the invention may be practiced

otherwise than as specifically described. Any reference to claim elements in the singular, e.g.

using the articles "a," "an," "the," or "said" is not construed as limiting the element to the

singular.

Claims

What is claimed is:

1. A system for producing synthetic hydrocarbons, comprising:

(a) a unit for recovering carbon dioxide from seawater, air, or a combination thereof;

(b) a unit for producing hydrogen from water; and

(c) a Fischer Tropsch synthesis unit wherein a reverse water gas shift reaction for intermediary carbon monoxide production or a Carnol or Lurgi process for intermediary

methanol production is combined with Fischer Tropsch synthesis to produce said

hydrocarbons from said carbon dioxide and said hydrogen.

2. The system of claim 1, wherein said carbon dioxide recovery unit is selected from the group consisting of: . . ^'.• ■ ■ ' :

(a) a partial vacuum, degassing processαised during the pumping of seawater, from any

depth;

(b) an extraction process for recovering carbon dioxide from seawater;

(c) an absorption process for recovering carbon dioxide from air; and

(d) any other process for recovering carbon dioxide from air or water; or

(e) any combination thereof.

3. The system of claim 1, wherein said hydrogen production unit is selected from the group

consisting of:

(a) an electrolysis process;

(b) a thermolysis process;

(c) a thermochemical process; and

(d) any combination thereof.

4. The system of claim 1, wherein the energy required for said hydrogen production unit is

provided by nuclear reactor electricity; nuclear reactor waste heat conversion; ocean thermal

energy conversion; any other non fossil fuel source such as waves, tide, wind, or ocean

current

energy; or combinations thereof.

5. The system of claim 1, wherein said Fischer Tropsch synthesis unit uses a catalyst

selected from the group consisting of:

(a) metals selected from the group consisting of iron, cobalt, and nickel, and

combinations thereof;

(b) metal oxides selected from the group consisting of iron oxide, cobalt oxide, nickel

oxide, ruthenium oxide, and combinations thereof; . . . .

(c) support type material selected from the group consisting of as alumina or zeolites;

(d) supported metals, metal oxides, mixed metals, or mixed metal oxides; and

(e) any combination thereof.

6. The system of claim 1, wherein said system is located on a structure at sea.

7. A process for producing synthetic hydrocarbons, comprising:

(a) recovering carbon dioxide from seawater, air, or a combination thereof;

(b) producing hydrogen from water; and

(c) reacting said carbon dioxide and said hydrogen with a catalyst in a chemical

process using:

(1) a reverse water gas shift for intermediary carbon monoxide production or a

Carnol or Lurgi process for intermediary methanol production; and (2) a Fischer Tropsch synthesis to produce said hydrocarbons from said

hydrogen and said intermediary carbon monoxide or methanol.

8. The process of claim 7, wherein said carbon dioxide recovery is selected from the group

consisting of:

(a) partial vacuum degassing during the pumping of seawater from any depth;

(b) extraction from seawater by any physical or chemical means;

(c) absorption from air by any known physical or chemical means; and

(d) any combination thereof.

9. The process of claim 7, wherein said hydrogen production is selected from the group consisting of:

(a) standard electrolysis of water; /

(b) thermolysis of water;

(c) thermochemical processes; and

(d) any combination thereof.

10. The process of claim 7, wherein the energy required for said hydrogen production is

current energy; or combinations thereof.

11. The process of claim 7, wherein said catalyst is selected from the group consisting of:

(a) metals selected from the group consisting of iron, cobalt, and nickel, and

combinations thereof; (b) metal oxides selected from the group consisting of iron oxide, cobalt oxide, nickel oxide, ruthenium oxide, and combinations thereof;

(c) support type material selected from the group consisting of alumina or zeolites;

(d) supported metals, metal oxides, mixed metals, or mixed metal oxides; and

(e) any combination thereof.

12. The process of claim 7 wherein said process is carried out on a structure at sea.